Polar biased relay



Dec. 13, 1949 o. s. FIELD l Pom Busan amr Original FiledOct. 14, 1940attorney Patented Dec. 13, 1949 POLAR BIASED RELAY Oscar S. Field,Rochester, N.

Y., assigner to General Railway Signal Company, Rochester, N. Y.Original application October 14, 1940, Serial No.

now Patent No.

Divided a 2,376,534, dated May nd this application April 17, 1945,Serial No. 588,748

3 Claims. (Cl. l75-'-339) This invention relates to electromagneticrelays for use on railways, and more particulary pertains to relays ofthe polar-biased type for distinctive response to polarized control.

This application is a division of my copending application Ser. No.361,060, filed October 14, 1940, which has resulted in a Patent No.2,376,534, dated May 22, 1945, in which the relay structure of thepresent invention besides operating relay contacts also acts to'operatethe movable spectacle of a searchlight type signal; and no claim isintended to be made in this application to subject matter claimed insuch patent.

One of the objects of the present invention is to provide a. relaystructure comprising two electromagnets each provided with a tractivetype armature, with one of the electromagnets being of the neutral typeresponsive to energization by current of either polarity, while theother electromagnet is of the polarized type responsive to energizationby current of only a particular polarity.

A further object of the present invention is to so organize thepolarized electromagnet that its amature will respond to the particularpolarity with a relatively small operating current; but will not beresponsive to energization by the opposite polarity even though thedegree of energization may be several times the degree of energizationrequired for operation by said particular polarity.

Another object of the present invention is to provide an electromagnetstructure of the polarized type which will not respond to eitherpolarity by the regular degree of operating energization in the eventthat the polarizing magnet becomes ineffective.

A further object of the invention is to provide the polarized andneutral electromagnets so associated with each other in a unitarystructure and circuit organization that the armature of the neutralelectromagnet will respond to either polarity and will remain picked upupon a relatively quick reversal of polarity; while the armature of thepolarized electromagnet will be actuated only in response toenergization by said particular polarity. It should be noted that thestructure and circuit organization effecting this feature have beendisclosed in my divisional application Ser. No. 782,211, filed October25, 1947, in which the subject matter involving the circuit organizationis being claimed.

Other objects, purposes and characteristic features of the presentinvention will be in part obvious from the accompanying drawings, and inpart pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to theaccompanying drawings, in which like reference characters designatecorresponding parts throughout the several views, and in which:

Fig. l illustrates in a diagrammatic and conventional manner the circuitorganization relating the electromagnetic structure of the presentinvention to an external control circuit;

Fig. 2 is a front elevation of a relay structure embodying the presentinvention;

Fig. 3 is a side view of the relay structure with parts shown in sectionas taken on line 3 3 of Fig. 2;

Fig. 4 is a top view of the relay structure embodying the presentinvention and shown in Fig. 2; and

Fig. 5 is a sectional view of the polarized electromagnet to show theshape of the molded permanent magnet.

The relay structure of the present invention comprises a frame member 15which is preferably molded of some suitable non-magnetic material, suchas brass, aluminum, Bakelite or the like. This frame structure 'i5 has ashelf extending across the back portion and protruding outwardly fromits back portion (as seen in Figs; 2 and 3) upon which the neutral andpolarized electromagnet relays NR and PR are mounted.

Referring to Fig. 2, it will be noted that each relay structurecomprises a core and winding structure, an associated tractive typearmature, and a contact group. For convenience, the armature of theneutral relay has been designated Y; while the armature of the polarizedrelay has been designated G. Each armature operates its group ofcontacts through suitable pusher members |20, as will presently bedescribed in greater detail. The polarized relay PR also includes apermanent magnet |55 as can best be seen in Fig. 4.

As can be most clearly seen in Fig. 4, the shelf portion 15 carries thetwo electromagnets or relays having coils and 9|, and these relays areplaced side by side and extending from rear to front of the shelf 15.Since these two relays are similar so far as their coil, armature andcontact structure is concerned, only one of them will be described indetail, and this description will be more particularly directed to thepolarized relay which includes the permanent magnet |55.

Referring to Fig. 3 which is a sectional view of the polarized relay PRtaken on line 3 3 of Fig. 2, it can be seen that a core 92 carries thewinding or coil 9|; is positioned above the shelf and isA connected in amagnetic circuit including downwardly extending legs 93 and 94, carryingpole pieces 95 and 96, with an airgap between their inner ends.

The armature G, as viewed in Fig. 3, is pivoted at its rear end by asuitable needle bearing such as disclosed in my copending applicationSer. No. 548,354, led August 7, 1944, now Pat. No. 2,435,000, datedJanuary 27, 1948, to which reerence may be made for the details of sucha bear ing. It is sufcient for the purposes of the present disclosure toknow that a flattened surface provided by a bearing plate |05 is held inposition by two depending legs upon which are mounted springs I|0, sothat a. needle bearing |08, which is received in a V-shaped slot in thetop face of the armature, is held in position between the armature andthe bearing plate |05. In other words, the armature G is pivoted on aspring biased adjustable needle bearing as disclosed in the abovementioned application.

At the other end, the armature G normally rests against the adjustableback stop 99 mounted upon a suitably extending arm |00. As shown, thearmature G is biased by gravity to its deenergized position. But in theparent application above referred to, a biasing spring was alsodisclosed for each armature to assure the restoration of that armatureto its deenergized position by compensating for the weight of thespectacle arm which was jointly operated by the armatures G and Ythrough the extending arms |33 and |25 respectively. Since the spectacleoperation has not been shown, the extending arms |33 and |25 have beenomitted. The additional spring biasing means has also been omitted sincethey are unnecessary for the disclosure of this application. However, itis to be understood that spring biasing means may or may not be employedas may be most desirable for the operatingvalues of the relay armatures.

As above mentioned, each of the armatures G and Y has associatedtherewith a group or bank of contacts. Each group of contacts comprisesa plurality of movable contact arms |23 which may be operated betweenback contact arms |22 and front Contact arms 2| by suitable pusher arms|20. The pusher arms are pivotally connected to their respectivearmatures by slotted boss members I |6 with a suitable pivoting pin I7which is anchored against endwise movement by a spring latch I8 carriedat one end by the lug H6 and at its other end springing into a notch II9 in pin I I. Since the movable contact springs |23 are normally heldagainst their respective back contacts by the weight of the associatedarmature, there is a certain spring pressure provided by the backcontact springs |22 which the weight of the armature normally opposes,but the weight of the armature is assumed to be sucient to overcome thisback spring pressure with plenty of margin. The fixed contact springs 2|and |22 together with the movable contact springs |23 with theirrespective adjusting arms are mounted or molded into a suitable contactblock |40 as viewed in Fig. 3, each contact of course having a suitableextension to the right of the block |40 to provide for the connection ofWire leads. These contacts mounted on the blocks |40 can be suitablyadjusted before they are inserted into the relay mechanism. When theblock |40 is mounted into its recess in the frame structure 15, asuitable mounting screw |4| at the top and a mounting screw |42 at thebottom are inserted so as to provide an adjustment o! the properlocation of the proper position, the contact block |40 being biasedoutwardly against the screw |42 from the frame 15 by reason of spring|43. When the proper adjustment has been made, the screw |4| istightened and a lock nut |44 is set in position. Referring to Fig. 2, itis seen that a plurality of these contact blocks and associated contactsare associated with each of the armatures, and each block is providedwith its adjusting screws. With this arrangement of contacts, a variablenumber of contacts can be associated with each armature without alteringthe design and proportions of the structure as a whole.

As above mentioned, the general magnetic structure of each relay PR andNR is the same,

but the polarized relay core structure includes soft iron extensions |35and |35, one at each end of the core 92, which extensions are held inposition against the respective legs 93 and 94 of the mag'- neticstructure by the bolts |56 which hold the core 92 in position. Parallelwith the core 92 and extending between the two soft iron extensions is apermanent magnet |55 held in position by suit.. able bolts |51, and thispermanent magnet is shaped to ilt around the coil 9| so as to conservespace and yet have the desired residual magnetic force.

In accordance with the present invention the permanent magnet |55 isprovided with such cross sectional area relative to the cross sectionalarea of the core member 92 that its degree of residual magnetismeffectively saturates the core member 92 with flux without producing anysubstantial degree of flux in the associated armature G. In other words,the close and intimate magnetic connection between the permanent magnet|55 through the extensions I 35 and |36 to the core member 92 provides amagnetic path of such low reluctance that there is only a relative smallleakage flux passing through the magnetic circuit including the armatureG and the air gap between it and the pole pieces 95 and 96.

Fig. 5 shows a cross-sectional view of the core member 92 and theassociated permanent magnet |55. From this it will be seen that thepermanent magnet |55 is clamped into position by bolts received in themolded recesses of the magnet. In this connection, it may be noted thatmodern manufacturing of permanent magnets is eiected by a molding orsintering process for economical production, and the structure of thepresent invention takes advantage of this fact.

Referring to the diagrammatic illustration of Fig. 1, it will be seenthat the neutral relay NR is associated with the polarized relay PRthrough a rectier unit |54 by suitable circuits including a manuallyoperable push button |53 and connected to terminals which may beenergized with current of either polarity as indicated by the symbolsand Both the armatures Y and G are shown as being connected to theirrespective movable contacts |23. The polarized relay PR has beenillustrated as having its permanent magnet |55 mounted above the core 92for convenience although it is actually at the side as shown in Fig. 2.This permanent magnet is magnetically connected in multiple with thecore 92, and it has sucient residual magnetism to substantially saturatethe associated core 92.

When the switch or push buttonlll is actuated to close the controlcircuit, and assuming that positive potential is placed on the lowerterminal while negative potential is placed on the upper terminal, thencurrent ilows through the lefthand portion of winding 9| on core 92,through the rectifier structure |54. winding 90 on the neup tral relayNR, through the rectifier |54, through the right-hand portion of thewinding 9| on core 92, to the other terminal. The current which 10 thusiiows in the winding 90 of the neutral relay acts to produce magneticflux in its core structure which is effective to actuate its amature Yto a picked up position.

The magnetic nux produced in the winding 9| on core 92 with thispolarity applied to thef circuit organization acts to produce a magneticflux which is in the same direction as the ilux of the permanent magnet|55 passing through the core 92, as indicated by the dotted arrowswithin the core 92 and the solid arrow in the permanent magnet |55.Since the residual magnetism of the permanent magnet |55 substanf tiallysaturates the core member 92, the energization of the winding 9| to theusual degree required for the operation of the neutral relay NR isineffective to produce anyl substantial change in the magnetic flux ofthe core structure. This will be better appreciated by realizing thatwhen a piece of soft iron is substantially saturated, the furtherenergization of an associated winding produces only that additional uxwhich would be produced if there were no iron core. This additional fluxproduced by such energization of the winding 9| has two possiblemagnetic paths, one 35 through the permanent magnet |55, and the otherthrough the armature G and the associated air gap. Regardless of theratio of division of this additional flux through its two possiblepaths, it does not actuate the armature G bei 40 cause it is ofinsufiicient value and also because that portion which may pass throughthe armature is in opposition to that leakage flux which is supplied bythe permanent magnet. Thus. it will be apparent that under theseconditions the armature G is not actuated; while the armature Yimmediately assumes its actuated position. For these reasons, it can beseen that to energize the winding 9| sumciently with such reversepolarity as to cause the actuation of the armature would require manytimes the normal degree of energization for the relays PR, and NR.

On the other hand, if the opposite polarity is applied to the terminalsof the circuit organization of Fig. l, it will be apparent that thedirection of magnetic flux in the core 92 will be reversed as indicatedby the associated solid line arrows; while the direction of the magneticflux produced in the neutral relay structure remains the same by reasonof the rectier unit |54. This opposite polarity will of course cause theactuation of the armature Y of the neutral relay. Also,

y the magnetic flux produced in the core 92 of the is a considerableincrease of magnetic flux passing through the air gap and the armature.This causes the armature G to be actuated or picked up thus operatingits associated contacts to open the back contacts and close the frontcontacts.

Thus, when the electro-magnetism is in the direction of the full arrow,the core shunt on the permanent magnet is choked out, and the armaturepicks up, but when the electro-magnetism is in the reverse direction ithas no efiect to speak of, since the permanent magnet has saturated thecore and the armature remains retracted.

From this it can be seen that the application of energy of one polarityon the circuit organization causes both armatures Y and G to respond;while the application of energy of the opposite polarity results in theresponse of only'the armature Y. If the reversal in polarity on theterminals of this circuit organization is relatively quick, it will beapparent that the armature Y will remain picked up. This is because therectifier unit |54 causes the winding 90 to always be energized bycurrent flowing in the same direction regardless of the polarity of thepotential applied to the terminals of the circuit organization, and alsobecause the rectifier unit |54 shunts the current induced in windingduring a change in flux conditions so as to actually delay the decay offlux passing through its core and associated armature. Thus, if thereversal oi polarity on the terminals of the circuit organization isrelatively quick, the magnetic ilux through the armature is maintainedabove that value necessary to hold the armature picked up during suchreversal.

The rectier unit |54 is connected, as described above, between thewindings of the polarized relay PR and the neutral relay NR in a mannerto have a portion of winding 9| between the rectier and the terminalsfor protection against lightning or other transient surges of potentialwhich may occur across the terminals of the circuit organization.

From the above description, it will be observed that the permanentmagnet |55 and the core 92 are magnetically in parallel through a closedmagnetic circuit; whereas this parallel magnetic structure has extendingpole pieces and 96 with an intervening air gap between them and thearmature G. Thus, the magnetic circuit involving the armature is ofhigher magnetic reluctance than the other two magnetic paths. For thisreason, the permanent magnet residual magnetism has practically noeffect normally on the armature G because such residual magnetism isshunted by the core 92. Similarly, should the permanent magnet lose itsresidual magnetism due to a stroke of lightning, severe vibration, orthe like, it in turn Would provide a shunt path for magnetism producedbythe energization of the coil 9|l and the armature would not respondunder a normal degree of energization of such winding.

In the drawings, Fig. l illustrates a circuit organization where it isassumed that ordinarily a particular potential will be applied to theenergizing circuit such as will in one case operate both relay armaturesand in the other case operate only one. However, it may happen due totransient line voltages, lightning surges and the like, that thepotential applied to the energizing circuit will be several times thenormal degree of energization required for operation of the relay. Inthe event that such an abnormal energizing potential is of the wrongpolarity for the normal' operation of the polarized relay, suchpotential still will not cause the response of the armature G. This isfor the reason above pointed out, namely, that the lines of flux inducedby the energization of the winding 9|` in such a direction are in thesame direction as the saturating magnetic flux from the permanentmagnet, and under such circumstances the winding can merely producelines of flux the same as if the iron core were not present.

A unitary relay structure has thus been shown and described ascomprising a unit which is particularly adaptable for use in polarizedcircuits, having one group of contacts which are controlled by a neutralrelay so as to respond to current of one polarity, and having anothergroup of contacts controlled by a polarized relay so as to respond tocurrent of only a particular polarity. Such a unitary structure isparticularly useful in control circuits for use along railroads and thelike where reliable relays are required, and where protection againstlightning surges and the like is necessary. Especially the provisionoflthe polarized relay of the unitary structure which assures properpolar response even in case of wide variations in the degree ofenergization, is highly desirable for safety circuits where vproperresponse to polarity is required.

In this connection, it should be understood that the principle of such apolarized relay may be employed in various types of relay structure andelectromagnetic devices; and that the polarized relay structure PR maybe used as a separate and individual device if desired.

Having thus described a relay structure and organization as one specicembodiment of the present invention, it is desired to be understood thatthis form is selected to facilitate in the disclosure of the inventionrather than to limit the number of forms which it may assume; and it isto be further understood that various modifications, adaptations andalterations may be applied to the specific form shown to meet therequirements of practice, without in any manner departing from thespirit or scope of the present invention except as limited by theappended claims.

What I claim is:

1. In an electromagnetic relay of the type which is operated in responseto one polarity of energization but not the other, a core structurehaving extending pole pieces and a portion adapted to receive windings,a pivoted armature mounted adjacent said pole pieces so as to cooperatetherewith and biased to a released position away from said pole pieces,a permanent magnet directly connected to said core structure in a mannerthat the winding portion thereof forms a magnetic path of low reluctancefor the permanent magnets residual ux, saidpermanent magnet beingproportioned relative to said winding portion of said core structure soas to eiectively saturate said winding portion Without afordingsuflicient flux through said pole pieces and said armature to overcomethe bias of said armature in either its released or operated position,and windings located on said winding portion of said core structure andenergizable with current of either-polarity, said windings whenenergized to an operating value with current of one polarity acting toinduce a magnetic ux in said winding portion of said core structure inopposition to the magnetic flux therein provided by said permanentmagnet to cause sufficient magnetic flux to pass from said pole piecesinto said armature to actuate it to an operated position in oppositionto its normal bias, said windings when energized to a comparable currentvalue of the opposite polarity failing to provide enough ux through saidarmature and said winding portion of said core structure by reason ofits saturated condition to overcome the bias of said armature in eitherits released or operated position.

2. In an electromagnetic relay of the type which is responsive to onepolarity of energization but not the other, a core structure of ageneral U-shape having at the ends of its legs enlarged pole pieces withflat surfaces in a common plane, an armature spanning said pole piecesand adapted to be actuated from a biased released position to anoperated position by magnetic ux passing through working air gaps, awinding on a portion of said core structure, a permanent magnetsupported in multiple with said winding portion of the core structurethrough intimate magnetic contact, said permanent magnet having across-sectional area proportioned relative to the cross-sectional vareaof said winding portion of said core structure so as to eiectivelysaturate said winding portion without providing suicient flux throughsaid working air gaps to operate said armature from its biased positionor hold it in its operated position, said winding when energized byoperating current of one polarity acting to oppose the magnetomotiveforce provided by said permanent magnet in said winding portion of thecore structure and to provide sufcient flux through said working airgaps and said armature to actuate it from its biased position to itsoperated position, said winding when energized with current of the otherpolarity even though of a greater magnitude failing to provide sunicientflux through said working air gaps and said armature to overcome itsbias in either the released or operated position.

3. In an electromagnetic relay of the type which is responsive to onepolarity of energization but not the other, a horizontal core andvertical legs attached thereto terminating with inwardly extendingenlarged pole pieces, a moveable armature extending across said polepieces with intervening air gaps and biased to a retracted position awayfrom said pole pieces, a winding on said core, a permanent magnet withsoft iron extensions fastened with intimate magnetic Contact to the endsof said core, said permanent magnet being proportioned relative to saidcore to eiectively saturate said core without providing sucient uxthrough said air gaps to move said armature from its retracted positionor hold it in its attracted position, said winding when energized withoperating current of one polarity acting to oppose the magnetization ofsaid core by said permanent magnet and provide sufficient flux throughsaid air gaps to operate said armature to its attracted position, saidwinding when energized with current of the opposite polarity even thoughof a greater magnitude being ineiective on account of the saturatedcondition of said core to provide flux through said air gaps sucient toovercome the bias of said armature in either its retracted or operatedpositions.

OSCAR S. FIELD.

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